Polar Aligning an AZ-EG6 GT with setting circles

[davidcox257]

Hi there,

Does anyone know the correct procedure to polar align an AZ-EQ6 GT using the setting circles in conjunction with the polar scope, please?. I have found instructions for other Sktwatcher mounts on the internet and the setting circle configuration isn't exactly the same as the AZ-EQ6 GT. When I try and use them I end up with an alignment that is 180 degrees out for some reason! ....

Thanks

David

[AlistairHowie]

Hi David

I can't help you with your specific question, but I do have one of these mounts. I just put the mount in the home position, look at the Synscan handset to see what time it is showing for the positioning of Polaris and then move the RA axis to put the polar scope reticle in approximately the right position, then I use the adjustment bolts to put Polaris in the right place.

I guess if you're using setting circles you want to be a little more accurate than that? Have you looked at EQMOD? That will rotate the mount to exactly the right position for you to centre Polaris.

[davidcox257]

Thanks Alistair - I assume you are happy with your alignment, tracking and GoTo's after following the procedure you mention, right?

When I do it I always end up with the GoTo's being OK but never perfect. The object will never be centred in my eyepiece (I use a 26mm Nagler on a Celestron 925HD - gives me approx 45' FOV). Objects are usually in the outer half of the FOV and I've also noticed that the same object is not always in the same place in the FOV depending on what I'd slewed to last. Let me explain; last night after aligning on Capella and then Alkaid (both stars in the centre of the FOV) I slewed back to Capella to find it was to the right of the FOV. I then slewed to Regulus (that was to the left of the FOV) and then back to Capella and that was now to the left of the FOV this time around. Seems strange - I'm not sure what I'm doing wrong - any ideas?

[AlistairHowie]

I'm probably not the right person to advise you here since I don't use my scope for visual, only imaging. I don't use the handset, I use planetarium software to direct my mount and then Astrotortilla software to plate solve where it is pointing to get precisely on target.

Pop over to the dedicated AZEQ6 thread and ask your question there, I'm sure you will get lots of input. While you're there you can see the guiding results I was getting using my polar scope alignment method (one of the last posts in the thread).

Just a quick thought re your actual question, though, do make sure that during alignment you always approach the target star from the recommended direction to minimise backlash issues. From below and the left from memory. That will definitely make a difference to the accuracy.

[Marki]

Hi DAvid

I have had the same issue as you. I find its getting better with practice though. I set my tripod to compass north and then level it with a decent line level before placing the mount on it. Once I've got everthing rigid, I visually put the polar scope Plough in the same orientation as on the sky and the use the alt/azi adjustments to move Polaris into the little circle. I've found being much more precise with inputting the time has improved my accurarcy a lot. Last night I followed a suggestion I read on the forum and put in the time about a minute ahead, and only pressed enter once my phone showed that time, to the second (might be worth doin gthis bit 20-30 secs in advance to allow for subsequent time in chosing alignment stars). The idea being that we're contiually moving whilst performing the alignment, and I'm not sure exactly at what point it all sets. If I can't get a decent lock quickly on a two star algnment (my view west is blocked, so I have to be choosy in my alignment stars), I'll start again, as the time setting willbe too far off, and hence targets will not be well placed in the ep on go-to, even where the alignment reads 'successful'.

Not perfect yet, but I'm considerably better than I was when I started. I only do visual though. I think Alistair's advice on approach direction is sensible, and I;ll try to follw this next time and see if that helps. Another piece of advice I've tried to follow is to use alignment stars in the same general area as where you want to concentrate your observing (assuming you plan a session in such a way - I know I don't ). Last night I found the tracking was more accurate than previouily, but I did notice that go-to lost accuracy in terms of placement of a target in the ep fov by the end of the night. It may be in part because I was selecting targets well away from where my alignment stars were though (Plus I think there was a brief clash of scope and legs when I was trying to hit a target nr the zenith).

Not sure if any if that is helpful. I just think practice helps, and until now, I;ve had only a few chances to get out and get to know how this mount works.

[davidcox257]

Mark and Alistair - thanks for some great suggestions - I'll give tham all a try and post the results in a few days

[davidcox257]

@Marki

Forgot to ask one question - you say you level the tripod with a decent line level - I'm not fully understanding how this would work with the mount and tripod - can you explain the process please?

Thanks

[lensman57]

Thanks Alistair - I assume you are happy with your alignment, tracking and GoTo's after following the procedure you mention, right?

When I do it I always end up with the GoTo's being OK but never perfect. The object will never be centred in my eyepiece (I use a 26mm Nagler on a Celestron 925HD - gives me approx 45' FOV). Objects are usually in the outer half of the FOV and I've also noticed that the same object is not always in the same place in the FOV depending on what I'd slewed to last. Let me explain; last night after aligning on Capella and then Alkaid (both stars in the centre of the FOV) I slewed back to Capella to find it was to the right of the FOV. I then slewed to Regulus (that was to the left of the FOV) and then back to Capella and that was now to the left of the FOV this time around. Seems strange - I'm not sure what I'm doing wrong - any ideas?

Hi,

Seems to be a backlash problem, try entering a value of backlash compensation in the hand set about 1/2 of the error that you guess you are getting , and then try . You may have to fiddle with this for a while. Also make sure that the mount is absolutely level, best done with the scope, weights etc on.

regards,

A.G

[Astro_Baby]

If your 180' out that suggests you are nbot takinmg account of the fact that the Polarscope presents an upside down view.

Have you checked that ?

The alignment procedure using setting circlkes will be identical to any other mount out there. They are all basically the same in this respect. Vixen use a different system I believe on their latest mounts and Takahashi I believe use a different system too but the Az EQ6 should be no different to a standard EQ6 in this regard.

The EQ6 doesnt work well usinmg the circles as the RA circle is too far removed from the Polarscope circle for it to be really useful. You could use the hour angle method using the RA scale only.

[Marki]

@Marki

Forgot to ask one question - you say you level the tripod with a decent line level - I'm not fully understanding how this would work with the mount and tripod - can you explain the process please?

Thanks

I set the tripod up and level the top before I put the mount head on it . Not sure if it make that much difference. I mainly do it because I can't quite see the bubble level on the mount well enough to be sure its properly level when seting up at night. Just have to be careful not to knock the tripod when I put the mount on it .

[foundaplanet]

and

and

by Dion at astroshed are well worth a watch.

I use the hour angle to set my alignment and providing that my scope is well balanced I find it very accurate and a good method. It is not often that I have problems with alignment and when I do it is usually because I am doing something wrong. I also do as Marki says and get it nice and level. Some say this is not that important and I kind of agree but for the extra couple of mins I feel it is very worth it.

I have written down the procedure in a little book for moments of brain death which is very often very handy.

[davidcox257]

Mark - OK understood - I just wish Skywatcher had engineered a truly level surface on the mount head so you could level it without having to take it off and use the tripod top...... BTW, what type of level do you use; a normal spirit level or a digital device - just wondering how accurate it needs to be - I suppose you could even use a plumb line on the tripod as an alternative, right?

[Ben_Jim]

I use a boat level similar to this one, astronomyshed, used and looking at my bubble level after is spot on

Jim